Volition refers to the faculty or power of using one's will. Antonyms for the phrase "does one's volition" would include terms like compelled, forced, obligated, and coerced. When someone is compelled to do something, they are being compelled by some outside force, rather than doing something by choice. Likewise, when someone is forced to do something, they are being forced by some outside force, rather than doing something by choice. Similarly, when someone is obligated to do something, they feel that they have no choice but to do it, while when someone is coerced, they are being manipulated into doing something against their will. In contrast, when someone uses their volition, they are using their own power of choice.